Preparation of phosphorus-containing olefin polymers and salts thereof



United States Patent 3,397,219 PREPARATION OF PHOSPHORUS-CONTAINING OLEFIN POLYMERS AND SALTS THEREOF John Frederick Ford and John Michael Wood, Sunburyoil-Thames, Middlesex, England, assignors to The British Petroleum Company Limited, London, England, a British joint-stock corporation No Drawing. Filed Mar. 19, 1964, Ser. No. 353,269 Claims priority, application Great Britain, Mar. 29, 1963, 12,510/63, 12,512/63 11 Claims. (Cl. 260-448) ABSTRACT OF THE DISCLOSURE Liquid phosphorus-containing polymers useful as lubricating oil additives can be prepared by a combined phosphorylation/ polymerization reaction of an alpha-olefin with a phosphorus halide in the presence of a Friedel- Crafts catalyst, the olefin being present in at least a :1 molar excess over the phosphorus halide, and the Friedel- Crafts catalyst being in at least a 1.521 molar excess over the phosphorus halide.

This invention relates to the preparation of phosphoruscontaining olefin polymers suitable for use as additives for improving the viscosity index and detergent/ dispersant properties of lubricating oils, and to lubricating compositions containing such polymers.

According to the invention, a liquid phosphorus-containing olefin polymer is prepared by reacting an olefin, preferably an alpha olefin having up to carbon atoms, with a phosphorus halide, preferably chloride or bromide, the molar ratio of olefin to phosphorus halide being 100:0.1-25, preferably 100:210, in the presence of at least 1.5 moles of a Friedel-Crafts catalyst per mole of phosphorus halide and at a temperature below 0 C. so as to produce a phosphohalogenated polymer, and hydrolyzing the latter compound to convert halogen groups present in the polymer to oxygen or hydroxyl groups.

In order to produce products that are liquid at normal ambient temperatures, it will be necessary in most cases to carry out the phosphorylation/ polymerization reaction at a temperature above 60 C. Suitable Friedel-Crafts catalysts include aluminum chloride, zinc chloride, antimony chloride, ferric chloride, stannic chloride, titanium chloride, boron trifluoride and hydrogen fluoride. Aluminum chloride is preferred.

It is not necessary to use more than two moles of catalyst per mole of phosphorus halide in order to obtain the desired product.

Suitable alpha olefins are the methyl-substituted butenes, pentenes and hexenes.

The hydrolysis reaction may conveniently be carried out by adding water to the phospho-halogenated polymer and refluxing. The hydrolysis is complete when the acidity of the reaction mixture ceases to increase.

The reaction is preferably carried out in an inert solvent such as a chlorinated hydrocarbon, e.g. methylene chloride, ethyl chloride, ethyl bromide or carbon tetrachloride.

According to a further feature of the invention, the hydrolyzed phosphorus-containing polymer produced as described above may be reacted with a basic compound, e.g. a hydroxide, oxide or alkaline-reacting salt of an alkaline earth metal, alkali metal or aluminum, to produce a neutral product which is more suitable for use as a lubricating oil additive. This neutralization step may be carried out by adding excess of the basic compound, e.g. 2-4 times the required amount based on the neutralization value of the polymer, and refluxing the reactants in an inert solvent e.g. one of the solvents mentioned above or, in this case, a hydrocarbon solvent e.g. n-heptane. Alternatively, where "ice there is used in the phosphorylation/ polymerization reaction, a Friedel-Crafts catalyst that can easily be converted into a basic compound, the neutralization step may be carried out in situ. For example, where aluminum chloride is used as the catalyst, after the hydrolysis reaction the aqueous layer may be neutralized with ammonia to convert the aluminum chloride to aluminum hydroxide and the mixture then refluxed to neutralize the polymer.

The invention also includes phosphorus-containing olefin polymers, or salts thereof, prepared as described above.

The invention further includes lubricating compositions consisting essentially of a major proportion of a lubricating base oil (which may be mineral or synthetic) and a minor proportion, e.g. 0.1 to 25%, especially 1-10%, by weight of the composition, of a phosphoruscontaining olefin polymer, or a salt thereof, as specified above.

The preparation of three polymers according to the invention (Polymers MW7(a), MW7(b) and MW8(a)) will now be described by way of example.

Polymer MW7( a) The following reactants were used:

4-methylpentene-1 (4-MP-l) mole 0) g 40.93 AlCl (10 mole g 6.497 PCl (5 mole cc 2.15

A mixture of 200 cc. methylene chloride, 6.497 g. AlCl and 2.15 cc. PO1 was cooled to -40 C., under a nitrogen atmosphere. 4MP1 was added slowly with stirring and some reaction occurred. After addition of about 15 g. of 4MP1 in this way, the rate of addition was speeded up by adding it in portions of about 5 g. A temperature gradient of 30 C. was obtained but the flask contents were not allowed to rise above 20 C. Polymer separated out in the vessel. After complete addition of the 4MP1, stirring was continued for a further 2 hours, allowing the contents of the flask to Warm up to 0 C.

The solution was then left overnight and by the following morning was found to have turned from a slight yellow colour to brown.

About 50 cc. water and 100 cc. CCL, were added and the mixture refluxed for 1 /2 hours to complete the hydrolysis. The organic phase was separated, washed three times with water, dried over anhydrous Na SO and evaporated on a water bath under reduced pressure.

The residual polymer was then heated to 200 C. at a pressure of 0.05-0.02 mm. Hg until no further light distillate was obtained. A nitrogen bleed was used.

The product was a very viscous polymer, slightly cloudy and of a pale brown colour.

Polymer MW7 (b) Reactants:

4-MP-1 (100 mole g 42.8 AlCl (10 moles g 6.79 PCl (5 mole cc 2.20

The reaction was carried out substantially as for MW7(a) except that the initial mixture was cooled to 50 C. Addition of 4MP1 produced no temperature increase and eventually all the monomer had been added. There was then a very rapid reaction after a further delay of 15 min. and the temperature rose but was quickly reduced to 30 C. Polymer was formed. In this case there was no delay between the end of the reaction and the addition of water. The hydrolysis reaction and working up of the product was carried out as for MW7(a) and the final 0 product was a viscous polymer faintly cloudy and of a pale yellow colour.

3 Polymer MW8 (a) 3.2 g. of Polymer MW7(a) were dissolved in n-heptane (100 ml.). Ba(OH) .8H O (0.325 g.: i.e., three times the amount required for neutralization), was added and the mixture refluxed for one hour, dried with anhydrous Na SO filtered and evaporated.

The product was a pale brown viscous liquid, similar in appearance to the parent polymer. It had a barium: phosphorus ratio of 1:4 which is in agreement with the neutralization value of the parent (unneutralized) polymer MW7(a) which had a hydroxylzph-osphorus ratio of 1:2.

The properties of polymers MW7(-a), MW7(b) and MW8(a) are given in the table below. The base oil used for the viscosity and viscosity index tests was a fully refined lubricating oil obtained from a Middle East crude oil.

The carbon sedimentation test gives an indication of the detergent/ dispersant proper-ties of the polymers by measuring their ability to retard the settling of a suspension of carbon black in n-heptane. In this test 0.05 g. of the material to be tested are weighed in a test-tube 6" x /2" and ml. n-heptane added; the material is dissolved by heating if necessary. 0.1 g. American Carbon Black Kosmos BB is added to the solution which is shaken vigorously and allowed to stand overnight. The next day the test-tube is inverted 10 times and the rate at which the carbon black falls to the bottom of the test-tube assesses the dispersant properties of the material. Comparative assessments are done by measuring the time taken for carbon black layer to fall below 1.2 cm. in height. The height of the solution at the beginning is 7.5 cm. Without an additive, the time for settling of the carbon black to 1.2 cm. was approximately one minute and with 0.05 g. poly 4-methylpentene-1 it was approximately 10 minutes.

The effectiveness of the polymers according to the invention in regard to VI-improvement and detergent/dispersant properties is clearly demonstrated by the results shown in the table.

TABLE MW7 (a) MW7 (b) MW8 (:1)

Phosphorus content, percent wt 1. 35 1. 34 1. 2 Barium content, percent wt. Nil Nil 1.34 Neutralization value, mg.

KOI-I/g. polymer 11. 9 12.0

38 13.99 C. 38 C. 99 C. 38 C. 99 C Kinematic Viscosity (centistokes):

No polymer 45. 64 6.2 45. 64 6.2 45. 64 6.2 2% wt. polymer 53. 33 7. 46 54. 75 7. 64 52. 7G 7. 46 4% Wt. polymer 65. 8. 80 (i8. 77 9. 1G 64. 23 8. 73 Viscosity Index:

No polymer 103 103 103 2% Wt. polymer. 110 112 112 4% wt. polymer... 116 116 116 Carbon sedimentation test (minutes):

No polymer 1 1 1 0.05 g. polymer 530 300 1, 800

We claim:

1. A process for preparing a liquid, phosphorus-containing olefin polymer, which comprises reacting an alpha olefin having up to twenty carbon atoms with a phosphorus halide, in the molar ratio of 100 parts of olefin to 2 to 10 parts of phosphorus halide, in the presence of at least 1.5 moles of a Friedel-Crafts polymerization catalyst per mole of phosphorus halide and at a temperature within the range 0 C. to 60 C. to produce a phospho-halogenated polymer, and hydnolyzing the latter.

2. A process according to claim 1, in which the olefin is one selected from the group consisting of methyl-substituted butenes, pentenes and hexenes.

3. A process according to claim 2, in which the olefin is 4-methylpentene-1.

4. A process according to claim 1, in which the phosphorus halide is phosphorus trichloride.

5. A process according to claim 1, in which the Friedel- Crafts polymerization catalyst is aluminum chloride.

6. A process according to claim 1, in which the molar amount of the Friedel-Crafts polymerization catalyst used is between 1.5 and 2 times the molar amount of the phosphorus halide.

7. A process according to claim 1, in which the hydrolysis of the phospho-halogenated polymer is carried out by adding water to the polymer and refluxing.

8. A process for preparing a salt of a phosphorus-containing olefin polymer, which comprises preparing a phosphorus-containing olefin polymer according to claim 1 and subsequently neutralizing it with a basic compound selected from the group consisting of alkaline-reacting salts of alkaline earth metals, alkali metals and aluminum.

9. A process according to claim 8, which comprises carrying out the neutralization by adding 2 to 4 times the required amount of the basic compound based on the neutralization value of the polymer and refluxing th reactants in an inert solvent.

10. A process for preparing a salt of a phosphoruscontaining olefin polymer which comprises preparing a phosphorus-containing polymer according to claim 1 using in the phosphorylation/ polymerization reaction a Friedel- Crafts polymerization catalyst that can easily be converted to a basic compound, and subsequently forming the said basic compound in situ and neutralizing the hydrolyzed polymer with it.

11. A process for preparing a salt of a phosphoruscontaining olefin polymer, which comprises: reacting an alpha olefin having up to twenty carbon atoms with a phosphorus halide in the molar ratio of parts of olefin to 2 to 10 parts of phosphorus halide, in the presence of at least 1.5 moles of aluminum chloride polymerization catalyst per mole of phosphorus halide and at a temperature within the range of 0 C. to 60 C. to produce a phospho-halogenated polymer; hydrolizing the phosphohalogenated polymer; reacting the hydrolized polymer with ammonia to convert the aluminum chloride to aluminum hydroxide; and, thereafter refluxing the mixture to neutralize the polymer.

References Cited UNITED STATES PATENTS 2,137,792 11/ 1938 Woodstock 260-448 2,286,794 6/1942 Dickey et a1 260500 3,232,883 2/1966 Le Suer 260-500 3,259,671 7/1966 Jungermann et al. 260-500 OTHER REFERENCES ThomasAnhydrous Aluminum Chloride in Organic ChemistryReinhold Publishing Corp., N.Y., 1941, pp. 796 and 797.

TOBIAS E. LEVOW, Primary Examiner.

H. M. S. SNEED, Assistant Examiner. 

